Here we go. It all started innocent enough. With some panels cut to specific sizes …
[/url]20180328_143120 by Cullen Graham, on Flickr[/IMG]
I wanted to design a floor standing pair of speakers, with incredible and effortless dynamics, with very realistic sounding instruments and voices. That "jump" factor, if you will. I wanted a fairly high efficiency, three way design, with the drivers mounted very close together. I wanted bass bins with a bolt in interchangeable port tuning system. I wanted the top cabinets to be extremely dead and resonant free, with the best diffraction possible within the design restraints. I'm looking for very powerful bass to 40 hz. And the highs need to sound like live percussion. (Almost forgot one of my main design goals; I want these to have ZERO mechanical vibrations, where they couple with the floor. Wait, what ?). These are made to ROCK!
I already have a pair of AMTs I love, in the small Heil monopoles. I did NOT want to be a lemming, lol. I did not want to use the Faital Pro line for mids or lows. I had been really trying to decide between the B&C 6MDM38 mids, and the Ciare NDK-6 1.5 mids. Then I realized they will countersink almost perfectly in the exact same routed hole for the front baffle! I get to have a DSP setting for both midrange drivers. I can switch them out if I want to! Modular design goals.
Wait, DSP ? Yes. These will be fully active, with onboard amplifiers. These should be DYNAMIC! More tomorrow.
[/url]20180401_133855 by Cullen Graham, on Flickr[/IMG]
[/url]20180403_125043 by Cullen Graham, on Flickr[/IMG]
[/url]20180526_201518(0) by Cullen Graham, on Flickr[/IMG]
[/url]20180526_201532 by Cullen Graham, on Flickr[/IMG]
[/url]20180609_120116 by Cullen Graham, on Flickr[/IMG]
[/url]20180610_115715 by Cullen Graham, on Flickr[/IMG]
[/url]20180610_115728(0) by Cullen Graham, on Flickr[/IMG]
I wanted to design a floor standing pair of speakers, with incredible and effortless dynamics, with very realistic sounding instruments and voices. That "jump" factor, if you will. I wanted a fairly high efficiency, three way design, with the drivers mounted very close together. I wanted bass bins with a bolt in interchangeable port tuning system. I wanted the top cabinets to be extremely dead and resonant free, with the best diffraction possible within the design restraints. I'm looking for very powerful bass to 40 hz. And the highs need to sound like live percussion. (Almost forgot one of my main design goals; I want these to have ZERO mechanical vibrations, where they couple with the floor. Wait, what ?). These are made to ROCK!
I already have a pair of AMTs I love, in the small Heil monopoles. I did NOT want to be a lemming, lol. I did not want to use the Faital Pro line for mids or lows. I had been really trying to decide between the B&C 6MDM38 mids, and the Ciare NDK-6 1.5 mids. Then I realized they will countersink almost perfectly in the exact same routed hole for the front baffle! I get to have a DSP setting for both midrange drivers. I can switch them out if I want to! Modular design goals.
Wait, DSP ? Yes. These will be fully active, with onboard amplifiers. These should be DYNAMIC! More tomorrow.
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I started on the top cabinets. I had never worked with a tiny .303 air volume before, and I had extra room in the mid/high cabs. I wanted very solid and dead top cabinets. So I decided to fill the void between the outer enclosure, and the two smaller enclosures inside with fine sand. Someone kindly modeled my 6" roundover top cabinets, and it showed super flat response from very little baffle diffraction. Each top enclosure has two hollow, 6" half round sides on it. I'm also filling these half rounds with fine sand. These should be VERY non resonant!
[/url]20180617_184954 by Cullen Graham, on Flickr[/IMG]
[/url]20180617_185153 by Cullen Graham, on Flickr[/IMG]
[/url]20180628_102959 by Cullen Graham, on Flickr[/IMG]
And after making sawdust for a while, this happened...
[/url]20180701_153430 by Cullen Graham, on Flickr[/IMG]
Next I glued the strips on the cabinet sides, which are guides for the half rounds. After that, you can see I traced each half round bottom, and cut out the wood half rounds, and glued them on. These made the bottoms for the sand filling.
[/url]20180703_103126 by Cullen Graham, on Flickr[/IMG]
Woah ! A woofer sneak peek!
[/url]20180703_171049 by Cullen Graham, on Flickr[/IMG]
[/url]20180703_172658 by Cullen Graham, on Flickr[/IMG]
[/url]20180705_140221 by Cullen Graham, on Flickr[/IMG]
Next I glued the strips on the cabinet sides, which are guides for the half rounds. After that, you can see I traced each half round bottom, and cut out the wood half rounds, and glued them on. These made the bottoms for the sand filling.
Woah ! A woofer sneak peek!
And this is the easy way to make half rounds on speakers. Quarter rounds of ANY size, can be done the exact same way, for straight side walls.
[/url]20180706_122134 by Cullen Graham, on Flickr[/IMG]
These voids can be left empty, or filled with anything you want to try! I like sand the best personally.
[url=https://flic.kr/p/28WFzFY]
20180706_122121 by Cullen Graham, on Flickr[/URL]
Once you undo the tape, and trim any excess adhesives away, you get this kind of thing happening ….
[/url]20180701_163458 by Cullen Graham, on Flickr[/IMG]
[/url]20180701_163454 by Cullen Graham, on Flickr[/IMG]
[/url]20180701_163440 by Cullen Graham, on Flickr[/IMG]
[/url]20180701_163515 by Cullen Graham, on Flickr[/IMG]
Nest I began the bracing, which can't be completed until MY slot load, vs port load set up is decided. More on that later.
[/url]20180707_154324 by Cullen Graham, on Flickr[/IMG]
[/url]20180707_140935 by Cullen Graham, on Flickr[/IMG]
Next I made a way to have different types of bass bin tuning options … Modular One
[/url]20180708_105938 by Cullen Graham, on Flickr[/IMG]
[/url]20180708_105948 by Cullen Graham, on Flickr[/IMG]
Which leaves me just about here ….
[/url]20180708_110101 by Cullen Graham, on Flickr[/IMG]
These voids can be left empty, or filled with anything you want to try! I like sand the best personally.
[url=https://flic.kr/p/28WFzFY]
20180706_122121 by Cullen Graham, on Flickr[/URL]Once you undo the tape, and trim any excess adhesives away, you get this kind of thing happening ….
Nest I began the bracing, which can't be completed until MY slot load, vs port load set up is decided. More on that later.
Next I made a way to have different types of bass bin tuning options … Modular One
Which leaves me just about here ….
I will know for sure in the future. One pair will find a new home, lol. Amazing to have a drop in comparison solution like this. I was ready to do a dance! LOL
There will be a pair of Aurum Cantus AST-25120s in the future. But at $600 for the pair, that will be a ways in the future. I have 4 more items to purchase first, to complete my build. The tweeters will be a luxury. To be honest, I am truly wondering if they can best the Heils over 3000hz. BUT, they can be crossed over as low as 1200 with ease. But then I would wonder why I spent a lot on a mid driver that only plays from 300hz to 1200hz
LOLHaving said all of the above, stripping the front finish material from the top cabinets, in order to FILL in the holes cut for the Heils, to then re-cut holes for the AST-25120s is going to be NOT as easy as the drop in mids !
So my design goals were: I wanted a fairly high efficiency, three way design, with the drivers mounted very close together. I wanted bass bins with a bolt in interchangeable port tuning system. I wanted the top cabinets to be extremely dead and resonant free, with the best diffraction possible within the design restraints.
Well … my drivers are definitely close enough together, lol. And the efficiency should be right around 94-95db. The top bins are going to be DEAD, and very heavy/solid. The bass bins are meeting criteria. So far, so good.
I am going to spread Bondo smooth on the roundovers on the top cabinets, and finish them with ….. ha ha! Will have to stay tuned for that part.
Then I add the internal wiring, fill them with sand, and seal the tops. I will add the top cap, and the top cabs will be finished.
I will be adding the bass bins internal lining, and seal the first one up completely. Then it will be time for the first port tuning! These could be playing tomorrow, if I had enough time.
Well … my drivers are definitely close enough together, lol. And the efficiency should be right around 94-95db. The top bins are going to be DEAD, and very heavy/solid. The bass bins are meeting criteria. So far, so good.
I am going to spread Bondo smooth on the roundovers on the top cabinets, and finish them with ….. ha ha! Will have to stay tuned for that part.
Then I add the internal wiring, fill them with sand, and seal the tops. I will add the top cap, and the top cabs will be finished.I will be adding the bass bins internal lining, and seal the first one up completely. Then it will be time for the first port tuning! These could be playing tomorrow, if I had enough time.
Nice project
Rob.
Ha ha ha! I was waiting on this, Rob. LOL I tried making a couple of jigs, but somehow each one I messed up before it was finished. So everything you see was freehand routed, with a 1/2 hp router, and a Dremel tool, without any guides. All freehand. Thus the mistakes I will be trimming with Bondo, before I finish them.
The tube was very easy to cut. I laid the tubing on the floor, flat against a wall to keep it perfectly straight and from moving. I then took a perfectly flat and straight 1" x 4" piece of aluminum bar I have, and placed it at approximately a 45 degree angle to the floor and tube, held it in place and drew a straight line the length of the tube. I then rotated the tube in a circle, to the next cut mark with the flat bar still in place, and made the second line down the tube, exactly half way around.
Keeping the tube in place, jammed against the wall. I took a BRAND NEW blade in an Olfa knife ( Narrower than a regular razor knife's blades are), and bracing my cutting hand against the wall, I was able to cut a perfectly straight cut on my line, down the length of the tube. Your mileage may vary here, as I also route freehand. It is easy to clamp a cut guide into place using your straight edge you used for marking, if you prefer.
The skinny blade on an Olfa style knife cuts the tubing like it wasn't there. Making for very easy straight cuts. You will be surprised how easy it is. And the inside of concrete tubes are faced with a water resistant finish, which prevents water based adhesives from swelling the carboard. I have used 30 minute set silicone, expanding foam ( my favorite ) , hot glue, wood glue, etc as an adhesive on these tubes. They all stick well. Taping, clamping, weighting down while using expanding foam is easiest, dries quickest, sands down easiest, and holds like it's never letting go.
While it is a slight learning curve to create it, following what I did in photos should prove to be way easier than you would think. I can now make the round sfor a pair of speakers, and glue them into place in about 1.5 hours. They are ready to mess with the next morning, or about 5 hours later if left in the sun.
Oh yeah... I put down a bead of the expanding foam first, then place the tube over it gently. I then take my pre cut pieces of the foil tape and gently push the tube into perfect alignment with the front side first, and tape that tightly into place. I then roll it to the back side and form and tape the back side of the tube into place. I then pull off my NECESSARY work gloves of choice, and wait for the foam to dry completely with CLEAN of spray foam hands, lol.
Here is another pair of speakers I am working on. These quarter rounds are made from 4" carboard tube. Made the same way.
[/url]20171206_160904 by Cullen Graham, on Flickr[/IMG]
[/url]20171206_160851 by Cullen Graham, on Flickr[/IMG]
[/url]20171206_160832 by Cullen Graham, on Flickr[/IMG]
Hope this help you out !
Keeping the tube in place, jammed against the wall. I took a BRAND NEW blade in an Olfa knife ( Narrower than a regular razor knife's blades are), and bracing my cutting hand against the wall, I was able to cut a perfectly straight cut on my line, down the length of the tube. Your mileage may vary here, as I also route freehand. It is easy to clamp a cut guide into place using your straight edge you used for marking, if you prefer.
The skinny blade on an Olfa style knife cuts the tubing like it wasn't there. Making for very easy straight cuts. You will be surprised how easy it is. And the inside of concrete tubes are faced with a water resistant finish, which prevents water based adhesives from swelling the carboard. I have used 30 minute set silicone, expanding foam ( my favorite ) , hot glue, wood glue, etc as an adhesive on these tubes. They all stick well. Taping, clamping, weighting down while using expanding foam is easiest, dries quickest, sands down easiest, and holds like it's never letting go.
While it is a slight learning curve to create it, following what I did in photos should prove to be way easier than you would think. I can now make the round sfor a pair of speakers, and glue them into place in about 1.5 hours. They are ready to mess with the next morning, or about 5 hours later if left in the sun.
Oh yeah... I put down a bead of the expanding foam first, then place the tube over it gently. I then take my pre cut pieces of the foil tape and gently push the tube into perfect alignment with the front side first, and tape that tightly into place. I then roll it to the back side and form and tape the back side of the tube into place. I then pull off my NECESSARY work gloves of choice, and wait for the foam to dry completely with CLEAN of spray foam hands, lol.
Here is another pair of speakers I am working on. These quarter rounds are made from 4" carboard tube. Made the same way.
Hope this help you out !
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I couldn't see any mistakes, I asked as I know they're a bugger to do and thought you may have an easy jig solution 
(when I've done them before I've drawn around the driver on a piece of 3mm mdf and cut it out with a jigsaw, then glued onto the baffle.)Rob.
I did not have as much time today as I had wished to work on the speakers. I did finish gluing up the bass bin's side, after lining the walls with Denim batts. I also cut a top plate for one of the top cabinets. I want to smooth the roundovers tomorrow, if at all possible. I am ready to FINISH the top cabs!
[/url]20180711_153704 by Cullen Graham, on Flickr[/IMG]
[/url]20180711_153758 by Cullen Graham, on Flickr[/IMG]
Here, you can see how the interchangeable port system will slide in from the bottom rear.
[/url]20180712_115553 by Cullen Graham, on Flickr[/IMG]
Here, you can see how the interchangeable port system will slide in from the bottom rear.
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